Adjustable structure for the footrest ring of a chair

ABSTRACT

An adjustable structure for the footrest ring of a chair includes a footrest ring, a sleeve, a nut, an adjusting rod and two retaining rings. The sleeve is received in a through hole of a fixed base of the footrest ring, having a wall cut with an oblique groove. The nut is secured in an insert hole of the fixed base of the footrest ring. The adjusting rod has one end screwed in the nut and another end extending out of the fixed base. The two retaining rings are respectively engaged in the engage groove at an upper and a lower outer wall of the sleeve. Thus, the footrest ring can conveniently be adjusted in height and stably positioned on the support tube of a chair.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an adjustable structure for the footrest ring of a chair, particularly to one able to adjust the footrest ring to be positioned at a required height on the support tube of a chair by turning an adjusting rod to resist against or disengage from a sleeve that is secured on the support tube of the chair.

2. Description of the Prior Art

A comparatively high chair is generally provided with a footrest ring on a support tube so that a sitter can comfortably rest his/her feet thereon. A conventional footrest ring is immovably fixed on the support tube of a chair; therefore, the conventional footrest ring cannot be adjusted in height in accordance with the length of a sitter's feet, rendering inconvenience in use. Another conventional footrest ring adjustable in position is to have an intermediate portion of the footrest ring bored with a fitting hole for fitting the footrest ring on the support tube of a chair. The fitting hole of the footrest ring has one sidewall threadably fixed therein with a turning knob to be turned tight to resist against the support tube or released from the support tube for adjusting the footrest ring to be positioned at a certain height on the support tube of a chair. However, the conventional footrest ring adjustable in position is only to have the inner end of the turning knob resisting against the outer wall of the support tube of the chair so their contact area is quite small and hence unable to stably position the footrest ring on the support tube of the chair and as a result, the footrest ring fails to be tightly constricted on the support tube and is liable to slip off.

SUMMARY OF THE INVENTION

The objective of this invention is to offer an adjustable structure for the footrest ring of a chair, able to adjust the footrest ring to be stably positioned at a required height on the support tube of a chair.

The adjustable structure for the footrest ring of a chair in the present invention includes a footrest ring, a sleeve, a nut, an adjusting rod and two retaining rings. The footrest ring is provided with a fixed base formed therein with a through hole having an inner wall disposed with a notch and having a wall bored with an insert hole communicating with the notch. The sleeve to be received in the through hole of the fixed base has an upper and a lower outer wall respectively formed with an engage groove, further having a wall cut with an oblique groove. The nut secured in the insert hole of the fixed base has one end provided with a stop edge to be set in the notch of the fixed base and its interior bored with a lengthwise insert hole that is formed with female threads on the inner wall. The adjusting rod has one end provided with male threads and threadably fixed in the interior of the nut and another end extending out of the fixed base of the footrest ring. The two retaining rings are respectively engaged in the engage groove at the upper and the lower outer wall of the sleeve.

Further, the through hole of the fixed base of the footrest ring has its topside formed with a recessed face for receiving one of the two retaining rings. Thus, retained and held by the two retaining rings, the sleeve can be stably positioned in the interior of the fixed base of the footrest ring.

BRIEF DESCRIPTION OF DRAWINGS

This invention will be better understood by referring to the accompanying drawings, wherein:

FIG. 1 is an exploded perspective view of an adjustable structure for the footrest ring of a chair in the present invention;

FIG. 2 is a perspective view of the adjustable structure for the footrest ring of a chair in the present invention;

FIG. 3 is a cross-sectional view of the adjustable structure for the footrest ring of a chair in the present invention;

FIG. 4 is a schematic view of the adjustable structure for the footrest ring of a chair, illustrating that an adjusting rod is turned inward to resist against the outer wall of a sleeve and fixed in position in the present invention; and

FIG. 5 is a schematic view of the adjustable structure for the footrest ring of a chair, illustrating that the adjusting rod is turned outward to disengage from the outer wall of the sleeve for facilitating adjustment of the footrest ring in the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A preferred embodiment of an adjustable structure for the footrest ring of a chair in the present invention, as shown in FIGS. 1-4, includes a footrest ring 1, a sleeve 2, a nut 3, an adjusting rod 4 and two retaining rings 5, 5′ as main components combined together.

The footrest ring 1 has a central portion provided with a fixed base 10 with an axial through hole 11, which has a topside formed with a recessed face 12 and an inner wall disposed with a notch 13. The fixed base 10 has a sidewall bored with an insert hole 14 communicating with the notch 13 and its outer wall set with a plurality of connecting ribs 15 spaced apart equidistantly.

The sleeve 2 to be received in the through hole 11 of the fixed base 10 of the footrest ring 1 has an upper and a lower outer wall respectively provided with an engage groove 20, 20′ and a sidewall cut with an oblique groove 21.

The nut 3 inserted in the insert hole 14 of the fixed base 10 of the footrest ring 1 has one end provided with a stop edge 30 to be fixed in the notch 13 of the fixed base 10 and an interior bored with an insert hole 31 provided with female threads 32 on the inner wall.

The adjusting rod 4 has one end formed with male threads 40 and threadably fixed in the nut 3 and another end extending out of the fixed base 10 of the footrest ring 1.

The two retaining rings 5, 5′ are respectively engaged in the engage groove 20 and 20′ at the upper and the lower outer wall of the sleeve 2.

In assembling, referring to FIGS. 1-4, firstly, set the nut 3 in the notch 13 of the fixed base 10 of the footrest ring 1 to have the nut 3 inserted in the insert hole 14 of the fixed base 10 and the stop edge 30 of the nut 3 fixed in the notch 13 of the fixed base 10. Next, secure the nut 3 in the insert hole 14 of the fixed base 10 in a way of soldering and then, position the sleeve 2 in the through hole 11 of the fixed base 10 and have the two retaining rings 5, 5′ respectively engaged in the engage groove 20 and 20′ at the upper and the lower outer wall of the sleeve 2, letting the two retaining rings 5 and 5′ respectively resisting on the recessed face 12 of the fixed base 10 and on the underside of the fixed base 10 and enabling the sleeve 2 to be secured in the fixed base 10 of the footrest ring 1 never to slip off. Subsequently, have one end of the adjusting rod 4, which is formed with male threads 40, inserted in the insert hole of the nut 3 to be screwed with the female threads 32 of the nut 3, thus finishing assembly of the adjustable footrest ring of a chair.

In using, referring to FIGS. 2-5, after the adjustable footrest ring 1 of this invention is assembled on the support tube 6 of a chair, as shown in FIG. 3, the sleeve 2 will be elastically expanded outward by means of the oblique cut groove 21, and when the adjusting rod 4 is turned clockwise and screwed in the interior of the nut 3, the inner end of the adjusting rod 4 will push against the outer wall of the sleeve 2 to make the sleeve 2 contracted elastically, as shown in FIGS. 3 and 4. At this time, the space of the oblique cut groove 21 of the sleeve 2 will become smaller and smaller to enable the inner wall of the sleeve 2 to fully and closely contact with the outer wall of the support tube 6 of a chair, able to enlarge contact area and increase frictional force between the sleeve 2 and the support tube 6. Thus, the footrest ring 1 can be stably positioned on the support tube 6 of a chair and impossible to become loosened and slip off. To adjust the footrest ring 1 to be positioned at a proper height on the support tube 6 of a chair, only turn the adjusting rod 4 counterclockwise and unscrew it toward the outer side of the nut 3, letting the inner end of the adjusting rod 4 no longer resist against the outer wall of the sleeve 2 to enable the sleeve 2 to recover its elasticity and expand outward, as shown in FIG. 5. Thus, the inner wall of the sleeve 2 will no longer closely contact with the support tube 6 of the chair and the footrest ring 1 can be adjusted in height on the support tube 6. After the footrest ring 1 is adjusted to a height required, the adjusting rod 4 is turned clockwise anew to have its inner end resisting against the outer wall of the sleeve 2 to make the sleeve 2 tightly constricted and positioned on the support tube 6 of the chair, convenient to adjust the footrest ring in height and able to stably position the footrest ring.

While the preferred embodiment of the invention has been described above, it will be recognized and understood that various modifications may be made therein and the appended claims are intended to cover all such modifications that may fall within the spirit and scope of the invention. 

What is claimed is:
 1. An adjustably structure for the footrest ring of a chair comprising: a footrest ring provided with a fixed base, said fixed base bored with a through hole in the interior, said through hole having an inner wall disposed with a notch, said fixed base having a wall bored with an insert hole, said insert hole communicating with said notch; a sleeve received in said through hole of said fixed base of said footrest ring, said sleeve having an upper and a lower outer wall respectively formed with an engage groove, said sleeve further having a wall cut with an oblique groove; a nut secured in said insert hole of said fixed base of said footrest ring, said nut having one end provided with a stop edge, said stop edge fixed in said notch of said fixed base, said nut bored with an insert hole in the interior, said insert hole formed with female threads on the inner wall; an adjusting rod having one end threadably fixed in the interior of said nut and another end extending out of said fixed base of said footrest ring, said adjusting rod having one end formed with male threads; and two retaining rings respectively engaged in said engage groove at the upper and the lower outer wall of said sleeve.
 2. The adjustable structure for the footrest ring of a chair as claimed in claim 1, wherein said through hole of said fixed base of said footrest ring is formed with a recessed face at the topside for receiving one of said two retaining rings.
 3. The adjustable structure for the footrest ring of a chair as claimed in claim 1, wherein said fixed base of said footrest ring has outer wall set with a plurality of connecting ribs spaced apart equidistantly. 